A colloid is matter microscopically dispersed evenly throughout another substance (from Wikipedia, the free encyclopaedia. Retrieved 18 Apr. 2012). Colloidal systems consist of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gaseous.
Another distinct property of colloidal systems is the size of the dispersed phase solids. They have a diameter between approximately 1 and 1,000 nanometers. Colloids of dispersed solid phases with particle sizes larger than 1 micrometer belong to the category of micro-colloidal systems.
Colloidal systems are prepared by homogenizing energy input dispersing large particles to the colloidal dimensions. Grinding and milling techniques are commonly used for subdivision of large solid particles. The methods are capable to disperse particles to a size, which is a result of equilibrium between the two processes: subdivision and aggregation under mechanical force.
The application of biomass or biomass derived products (e.g. from herbs) has become progressively more popular in animal and human nutrition as well as in cosmetics and medicine. Their use relates to the fact that biomass, in particular of microbial, fungal and plant origin, contain active ingredients, so called bio-actives, which denote substances that have an effect on living systems (for a review see Ncube et al., African Journal of Biotechnology, 7, 1797-1806, 2008).
Although the effects of bio-actives have not always been formally and scientifically researched, their popularity is based on a long track record validating their safety and efficacy. With recent advances in medical and nutrition sciences, natural products and health-promoting foods have received extensive attention from both health professionals and the general population. Increasing knowledge from food chemistry, nutritional, and clinical studies is providing more insight into our understanding of biological functions, usage, and potential adverse effects of bio-actives. This advanced knowledge also calls for standardized manufacturing processes and clinical practices and at the same time could add more value to bio-active markets.
When applying bio-actives in animal and human nutrition or in cosmetics an important issue is whether to use the whole biomass or whether to supply the bio-actives in standardized extracts from biomass. A standardized extract contains one or more bio-active components in a specific, guaranteed amount. The intention behind the standardization is to guarantee that the consumer is getting a product in which the quality is consistent from batch to batch.
Unfortunately, while scientists can isolate many constituents from biomass and discover how particular chemicals may act in the body, they inadvertently remove or overlook components that may contribute to the activity of the whole biomass. Consequently, standardization may concentrate one constituent at the expense of other potentially important ones, while changing the natural balance of the bio-actives in the entire biomass.
Standardization, therefore, is based on the idea that isolated compounds are responsible for the bio-activity of biomass. In fact, biomass contains a complex blend of bio-actives. The full bio-active value of biomass is most likely due to their internal complexity and to the interactions of the different components within the body rather than to one of its specific components.
Furthermore, many of the constituents of biomass are as yet unknown and internal chemical interactions within and among biomass are even more poorly understood. Therefore, application of isolated enriched bio-actives may not be advisable and it is doubtful that this type of standardized biomass extracts can exhibit the same full spectrum of activity as the whole biomass. However, science has proven the efficacy of some of these concentrated extracts regarding specific biological activities, so they can be very useful even if they do not work exactly like whole biomass.